a) Field of the Invention
The invention relates to a device for generating an artificial constriction in the gastrointestinal tract with a band, which can be placed annularly about a particular portion of the gastrointestinal tract. By means of a piston-cylinder unit, the size of the throughlet opening of the portion of the gastrointestinal tract, encompassed by the band, can be varied. The band is connected in the proximity of its first end with the cylinder of the piston-cylinder unit.
b) Description of Related Prior Art
A device for generating an artificial constriction in the gastrointestinal tract is known for example in the form of a gastric band from EP 0 702 529 B1. The device comprises a band, which can be placed about the inlet of the stomach and which is developed with an inner hollow chamber extending longitudinally. For the closure of the band placed annularly about the inlet to the stomach, the band comprises a closure device with a first closure part, disposed on one end of the band and having an insertion opening, and a second closure part, disposed at the other end of the band, which can be introduced through the insertion opening and can be latched with respect to it. To constrict the cross section of the passageway of the throughlet opening of the band, and consequently of the inlet to the stomach, the hollow chamber of the band is filled with a filling medium, and the quantity of the filling medium depends on the desired passageway cross section. An injection port connected to the band is provided for filling the band with the filling medium. The injection port is implanted under the skin of the patient.
Apart from its development as a stomach band, a device of this type can especially also be developed as an anal band for the closure of an optionally artificial anus.
One problem encountered in such devices is that, sooner or later in the course of their use, they can leak, such that their function is no longer ensured. Surgical removal and replacement of this band is subsequently required, which is tied to a corresponding strain on the patient. Such leaks occur in practice, particularly in the diaphragm delimiting the band toward the throughlet opening. Such leaks can occur, for example, due to material fatigue in the course of use or due to overfilling of the band. For so-called “early” leaks, which occur up to approximately one year after the placement of the band, injury to the band is most often responsible, which injuries have occurred through a surgical instrument during the operative, in particular laparoscopic, placement of the band.
A device of the type described in the introduction is disclosed in U.S. Pat. No. 6,470,892 B1. The band here comprises a core encompassed by a tube. In one embodiment a piston-cylinder unit is provided, whose cylinder is disposed at one end of the band and whose piston is connected with a traction cord to the core, which terminates at a distance from this end of the band. By displacing the piston, the core within the tube is displaced and the band; closed annularly via a closure, is drawn together. Of disadvantage in this band is inter alia its relatively complicated structure.